The objective of this project is to acquire, make available, and support mathematical modeling and data analysis software systems that are accessible to investigators from many disciplines. The principals involved develop, test and implement such software on DCRT-supported computing platforms. They develop supplementary software and utilities to optimize the use and efficiency of such software systems. In addition, consultation and training are made available both through formal DCRT-sponsored courses and through individual consultations. In FY'92, all DCRT versions of PC MLAB were upgraded to the current versions and a course on its use was taught. Consultations were made to several IRP investigators and software exchange and upgrades were carried out in cooperation with the Computer Systems Laboratory. The tutorial manual was updated to reflect the new MLAB features and copies were distributed to class attendees. New smaller versions of PC MLAB are available at reduced cost ($1,000 per copy) and the software retains most of the important features of the fully developed version. These features include least squares model fitting of functional models and models represented by systems of ordinary differential equations. This version should be satisfactory for the majority of laboratory applications. When a model exceeds the capacity of the reduced version, full capability versions are available for NIH investigator use in the DCRT Scientific Computing Resource Center (SCRC) or in an auxiliary facility. Investigators should contact the SCRC for more information.